In 1782 two French brothers, Joseph and Etienne Montgolfier discovered that hot air was able to make objects such as paper and silk bags rise. They experimented for almost a year and on 5th of June 1783 in the village of Annonay, France, they inflated a silk bag 9 meters in diameter with heat from a fire. It rose more than 1 mile into the air before the air cooled and it drifted back to earth.
In September of that year Joseph Montgolfier sent a sheep, a rooster and a duck up in a `balloon' to see what would happen to them. As they landed, apparently unharmed, he decided the time had come for the first human flight. Jean-Francois Pilatre de Rozier and the Marquis d'Arlandes were the first volunteers. On November 21st 1783 they took off from Paris and stayed in the air for 23 minutes.
Throughout the 18th century many advancements were made. The first aerial crossing of the English Channel was successfully completed by Frenchman J.P. Blanchard and American John Jeffries on the 7th of January 1785.
Around the beginning of the 1930's scientists began to use balloons to study the atmospheric conditions at high altitudes. They are still used scientifically today and are also still very popular as a sport and leisure pastime.
The heat to inflate the balloon and make it rise is generated by a blast flame burner. The air expands, the overall load of the balloon lessens, and the upthrust transports the balloon upwards.
If the burner is turned off the air within the balloon will gradually cool and contract, becoming heavier. Additional air will then enter the balloon and increase its weight, causing it to lower. If fast descent is required, it can be achieved by opening a port at the uppermost part of the balloon. This fractionally deflates it and reduces the upthrust.
The hot-air balloon has no propelling equipment and therefore coasts with the wind. Periodic blasts of the burner enable the balloon to remain at a consistent height.
